You can search for metafields by product titles in the application. But due to the limited nature of Shopify API (the application access everything related to your store using Shopify's API), the search is not very efficient. It is a lot easier to search for products or variants in Shopify Admin area. Type in the search terms in Shopify admin and find your product. Once you find the products in Shopify, click on the link that says more actions at the top of the product page and choose View Metafields. See screenshot below. This will bring you to the application and show the metafields related to the products.